Asked about the shifting timeline on Sunday as he left the White House for meetings about border security at Camp David, Mr. Trump told reporters that he had “never said we were doing it that quickly.” In a video on the evening of his announcement in December, he had said that “our boys, our young women, our men — they’re all coming back, and they’re coming back now,” though he later extended that to four months.
Now, the four-month schedule appears highly in doubt. The conditions Mr. Bolton described, including the complete defeat of the Islamic State and the guarantees from Turkey, could easily stretch out.
Mr. Bolton will meet on Tuesday with President Recep Tayyip Erdogan of Turkey, who argued to Mr. Trump in a phone call last month that the Islamic State had been defeated, and that American troops were therefore no longer needed to aid Kurdish fighters. Turkey considers the Kurdish forces a terrorist body bent on carving out a separate nation.
Before the Turkey visit, Mr. Bolton was expected to meet with Prime Minister Benjamin Netanyahu of Israel over dinner on Sunday evening. Mr. Netanyahu has also been concerned about the American plan, for fear it will leave a vacuum and embolden Iran.
In Jerusalem, Mr. Bolton described the conditions as “policy decisions that we need to implement,” and he said a timeline for a withdrawal would be necessary only once those stipulations were met. He said that Gen. Joseph F. Dunford Jr., the chairman of the Joint Chiefs of Staff, would negotiate with Turkish officials this week over the protection of the Kurdish fighters.
Mr. Bolton’s comments seemed to expand on a classified memo he wrote to cabinet officials on Dec. 24 that outlined a strategy for Turkish troops to replace the roughly 2,000 American troops conducting counterterrorism operations against the Islamic State in northeastern Syria, according to two Defense Department officials.
Mr. Bolton’s memo came after Mr. Trump and Mr. Erdogan spoke by phone on Dec. 23. After that conversation, Mr. Trump tweeted: “I just had a long and productive call with President @RT_Erdogan of Turkey. We discussed ISIS, our mutual involvement in Syria, & the slow & highly coordinated pullout of U.S. troops from the area. After many years they are coming home.”